Technical Field
The present disclosure relates generally to systems and methods for welding metal components to form medical devices. More particularly, the present disclosure relates to systems and associated methods for laser welding a nickel titanium alloy with a dissimilar metal or metal alloy to form a bimetal medical device.
Description of Related Art
Guidewires are commonly used in medical procedures to assist in the advance and proper positioning of a catheter or other medical device in lumens, vessels, or other cavities of the body. Neurovascular procedures utilizing guidewires include the imaging and treatment of aneurysms, arteriovenous malformations (AVM), and ischemic stroke. The effectiveness of an intravascular guidewire in advancing through tortuous neurovasculature without undesired deformation or kinking is dependent upon a number of factors and design considerations. These factors include, inter alia, the material(s) of fabrication of the guidewire, guidewire dimensions and intended use. Generally, a balance must be achieved to provide the required torsional, lateral, tensile and/or column strengths to enable easy and precise manipulation and steerability in the tortuous vasculature. Guidewires for such endovascular procedures face additional challenges due to the relatively small diameter required to navigate through the narrow and remote locations of the neurovasculature.
A guidewire, for example, may be formed from two materials to provide variable stiffness to the device by having a relatively stiff proximal portion to facilitate pushing of the guidewire through the vasculature and a relatively flexible distal portion to facilitate steering of the guidewire through the vasculature. Various techniques for forming a guidewire with variable stiffness include joining a nickel titanium alloy and a dissimilar metal. Known techniques utilize an intermediate material between the two metal components to achieve a strong joint therebetween, an external sleeve or outer layer to reinforce the joint between the two metal components, or mechanical fasteners to join the two metal components together.